ORCID Profile
0000-0003-4974-1670
Current Organisation
Universidad de Las Palmas de Gran Canaria - Campus de Tafira
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Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CP02844G
Abstract: A series of NHC-gold(i) (NHC = N-heterocyclic carbene) complexes has been studied by DFT calculations, enabling comparison of electronic and NMR behaviour with related protonated and free NHC molecules. Based on calculations, the NMR resonances of the carbenic C2 carbon atom in [Au(NHC)(Cl)] and [NHC(H)][Cl] exhibit increased shielding when compared to the free N-heterocyclic carbenes by an average of 46.6 ± 2.2 and 73.7 ± 4.3 ppm, respectively. A similar trend is observed when analysing the paramagnetic term of the magnetic shielding tensor. Although gold(i) and proton are considered isolobal fragments, imidazolium compounds lack π-backdonation due to the energetic unavailability of d-orbitals in H+. We propose that NHC-gold(i) complexes exhibit important π-backdonation irrespective of the relative amount of σ-donation between the NHC and gold(i)-X (X = anionic ligand) moieties in Au-NHC complexes. Interestingly, a correlation exists between the calculated shielding for gold (197Au) and the π-donation and π-backdonation contributions. We describe that this correlation also exists when analysing the σ-backdonation term, a property generally ignored yet representing a significant energetic contribution to the stability of the C2-Au bond.
Publisher: Wiley
Date: 03-09-2018
Abstract: The first base-metal-catalysed hydrogenation of CO
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CP02380C
Abstract: SO 3 and H 2 CO dimers and trimers are held together by S⋯O chalcogen bonds, supplemented by weaker CH⋯O and/or O⋯C bonds.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0CP01321H
Abstract: Dianion dimers trapped inside cyanostar macrocycles are supported by interanionic H-bonds, π–π stacking between confronted cyanostars, and an intricate network of multiple C(sp²)H⋯O H-bonds between the cyanostar and the anionic moieties.
Publisher: Elsevier BV
Date: 04-2023
Publisher: Elsevier BV
Date: 10-2022
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3NJ01076G
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CP51963E
Abstract: The mechanism of the S(N)2 model glycosylation reaction between ethanol, 1,2-ethanediol and methoxymethanol has been studied theoretically at the B3LYP/6-311+G(d,p) computational level. Three different types of reactions have been explored: (i) the exchange of hydroxyl groups between these model systems (ii) the basic catalysis reactions by combination of the substrates as glycosyl donors (neutral species) and acceptors (enolate species) and (iii) the effect on the reaction profile of an explicit H2O molecule in the reactions considered in (ii). The reaction force, the electronic chemical potential and the reaction electronic flux have been characterized for the reaction path in each case. Energy calculations show that methoxymethanol is the worst glycosyl donor model among the ones studied here, while 1,2-ethanediol is the best, having the lowest activation barrier of 74.7 kJ mol(-1) for the reaction between this one and the ethanolate as the glycosyl acceptor model. In general, the presence of direct interactions between the atoms involved in the penta-coordinated TS increases the activation energies of the processes.
Publisher: No publisher found
Date: 2018
Publisher: American Chemical Society (ACS)
Date: 12-11-2020
Publisher: Wiley
Date: 16-08-2016
Publisher: Wiley
Date: 25-11-2020
Abstract: It has become apparent that renewable energy sources are plentiful in many, often remote, parts of the world, such that storing and transporting that energy has become the key challenge. For long-distance transportation by pipeline and bulk tanker, a liquid form of energy carrier is ideal, focusing attention on liquid hydrogen and ammonia. Development of high-activity and selectivity electrocatalyst materials to produce these energy carriers by reductive electrochemistry has therefore become an important area of research. Here, recent developments and challenges in the field of electrocatalytic materials for these processes are discussed, including the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER), and the nitrogen reduction reaction (NRR). Some of the mis-steps currently plaguing the nitrogen reduction to ammonia field are highlighted. The rapidly growing roles that in situ/operando and quantum chemical studies can play in new electromaterials discovery are also surveyed.
Publisher: Springer Science and Business Media LLC
Date: 16-02-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2CC06967A
Abstract: Herein, we report an intramolecular endo -selective Heck reaction of iodomethylsilyl ethers of phenols and alkenols.
Publisher: American Chemical Society (ACS)
Date: 15-05-2014
DOI: 10.1021/JP501932G
Abstract: The SO
Publisher: Wiley
Date: 18-05-2014
Abstract: A theoretical study of the conformational profile of two diphosphines, PH2-PH2 and PH2-PHF, is carried using second-order Møller-Plesset perturbation theory (MP2) computational methods. The chiral minima found are used to build homo- and heterochiral dimers. Six minima are found for the (PH2-PH2 )2 dimers and 27 for the (PH2-PHF)2 dimers. Pnicogen and hydrogen bonds, the non-covalent forces that stabilize the complexes, are characterized by Atoms in Molecules (AIM) and Natural Bond Orbital (NBO) methodologies. Those with several pnicogen bonds are more stable than those with hydrogen bonds. The chirodiastaltic energies amount to a total of 1.77 kJ mol(-1) for the Ra:Ra versus Ra:Sa (PH2-PH2 )2 dimers, 0.81 kJ mol(-1) for the RSa:RSa versus RSa:SRa (PH2-PHF)2 dimers, and 2.93 kJ mol(-1) for the RRa:RRa versus RRa:SSa (PH2-PHF)2 dimers. In the first and second cases, the heterochiral complex is favored whereas in the third case, the homochiral complex is favored.
Publisher: AIP Publishing
Date: 27-06-2014
DOI: 10.1063/1.4884962
Abstract: The (O3)2 dimer potential energy surface is thoroughly explored at the ab initio CCSD(T) computational level. Five minima are characterized with binding energies between 0.35 and 2.24 kcal/mol. The most stable may be characterized as slipped parallel, with the two O3 monomers situated in parallel planes. Partitioning of the interaction energy points to dispersion and exchange as the prime contributors to the stability, with varying contributions from electrostatic energy, which is repulsive in one case. Atoms in Molecules analysis of the wavefunction presents specific O⋯O bonding interactions, whose number is related to the overall stability of each dimer. All internal vibrational frequencies are shifted to the red by dimerization, particularly the antisymmetric stretching mode whose shift is as high as 111 cm−1. In addition to the five minima, 11 higher-order stationary points are identified.
Publisher: American Chemical Society (ACS)
Date: 30-03-2018
Publisher: American Chemical Society (ACS)
Date: 24-09-2021
Publisher: AIP Publishing
Date: 14-07-2014
DOI: 10.1063/1.4890120
Publisher: Royal Society of Chemistry
Date: 2018
Publisher: American Chemical Society (ACS)
Date: 28-12-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2TA02187K
Abstract: An ultrathin carbon quantum dots modified hydrogenated mesoporous SrTiO 3 heterostructure (CQDs/STO) has been developed as a bifunctional catalyst for enhanced photoelectrochemical nitrogen reduction, resulting in a ∼50% increase in the ammonia yield.
Publisher: American Chemical Society (ACS)
Date: 24-11-2020
Publisher: Springer Science and Business Media LLC
Date: 30-04-2019
Publisher: American Chemical Society (ACS)
Date: 20-10-2023
Publisher: AIP Publishing
Date: 20-01-2015
DOI: 10.1063/1.4905899
Abstract: The complexes formed by H2CO, CH3CHO, and (CH3)2CO with 1, 2, and 3 molecules of CO2 are studied by ab initio calculations. Three different types of heterodimers are observed, most containing a tetrel bond to the C atom of CO2, and some supplemented by a CH⋅⋅O H-bond. One type of heterodimer is stabilized by an anti-parallel arrangement of the C=O bonds of the two molecules. The binding energies are enhanced by methyl substitution on the carbonyl, and vary between 2.4 and 3.5 kcal/mol. Natural bond orbital analysis identifies a prime source of interaction as charge transfer into the π*(CO) antibonding orbital. Heterotrimers and tetramers carry over many of the geometrical and bonding features of the binary complexes, but also introduce O⋅⋅O chalcogen bonds. These larger complexes exhibit only small amounts of cooperativity.
Publisher: Elsevier BV
Date: 09-2012
DOI: 10.1016/J.CARRES.2012.06.011
Abstract: The potential energy surfaces for the different configurations of the D-erythrose and D-threose (open-chain, α- and β-furanoses) have been studied in order to find the most stable structures in the gas phase. For that purpose, a large number of initial structures were explored at B3LYP/6-31G(d) level. All the minima obtained at this level were compared and duplicates removed. A further reoptimization of the remaining structures was carried out at B3LYP/6-311++G(d,p) level. We characterized 174 and 170 minima for the open-chain structures of D-erythrose and D-threose, respectively, with relative energies that range over an interval of just over 50kJ/mol. In the case of the furanose configurations, the number of minima is smaller by approximately one to two dozen. G3B3 calculations on the most stable minima indicate that the α-furanose configuration is the most stable for both D-erythrose and D-threose. The intramolecular interactions of the minima have been analyzed with the Atoms in Molecules (AIM) and Natural Bond Orbital (NBO) methodologies. Hydrogen bonds were classified as 1-2, 1-3 or 1-4, based on the number of C-C bonds (1, 2 and 3, respectively) that separate the two moieties participating in the hydrogen bond. In general, the AIM and NBO methodologies agree in the designation of the moieties involved in hydrogen bond interactions, except in a few cases associated to 1-2 contact which have small OH···O angles.
Publisher: American Chemical Society (ACS)
Date: 11-07-2022
Publisher: Wiley
Date: 04-09-2018
Abstract: The electrochemical nitrogen reduction reaction (NRR) under ambient conditions is a promising alternative to the traditional energy-intensive Haber-Bosch process to produce NH
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0CC05921H
Abstract: Cobalt-molybdenum alloys can stabilise the elusive N 2 H as the first reduced intermediate species in nitrogen reduction reaction (NRR).
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0CC02881A
Abstract: An unprecedented base metal catalysed asymmetric synthesis of α-chiral amine precursors from racemic alcohols is reported.
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.CARRES.2013.01.013
Abstract: The acid catalysis of the mutarotation mechanism in the two aldotetroses, d-erythrose and d-threose, has been studied at B3LYP/6-311++G(d,p) computational level in gas phase and in solution employing the PCM-water model. The open-chain, the furanose and the connecting TS structures have been characterized. To study the enhancing effect of acid groups on the electrophilicity of the carbonyl carbon atom, four situations have been considered: (i) a classical Lewis acid as BH3 (ii) a classical hard-Pearson acid as Na(+) (iii) classical Brønsted acids as H(+) and H3O(+) and (iv) a combined strategy using H3O(+) and one bridge-H2O molecule as assistant in the proton transfer process. All the acidic groups reduce the activation energy with exception of the Na(+), which can act, in some cases, as inhibitor. It is greatly reduced by the presence of Brønsted acids (iii) and through the combined strategy (iv). For this last mechanism, the electronic activation energies are between 12 and 43 kJ mol(-1) in vacuum and between 13 and 25 kJ mol(-1) in water solution, through the use of the PCM model.
Publisher: American Chemical Society (ACS)
Date: 25-04-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7CP07685A
Abstract: The interaction between the active site and the surrounding protein environment plays a fundamental role in the hydrogen evolution reaction (HER) in [NiFe] hydrogenases.
Publisher: Wiley
Date: 19-05-2017
Abstract: Based on the structure of the nitrogenase FeMo cofactor (FeMoco), it is reported that Fe deposited on MoS
Publisher: American Chemical Society (ACS)
Date: 25-07-2012
DOI: 10.1021/JP304495F
Abstract: The reaction mechanism of the hemiacetal formation from formaldehyde and methanol has been studied theoretically at the B3LYP/6-311++G(d,p) level. In addition to the study of the reaction between the isolated reactants, three different kinds of catalysis have been explored. The first one examines the use of assistants, especially bridging water molecules, in the proton transfer process. The second one attempts to increase the local electrophilicity of the carbon atom in formaldehyde with the presence of a Brønsted acid (H(+) or H(3)O(+)). The last one considers the combined effect of both catalytic strategies. The reaction force, the electronic chemical potential, and the reaction electronic flux have been characterized for the reaction path in each case. In general, it has been found that structural rearrangements represent an important energetic penalty during the activation process. The barriers for the reactions catalyzed by Brønsted acids show a high percentage of electronic reorganization contribution. The catalytic effects for the reactions assisted by water molecules are due to a reduction of the strain in the transition state structures. The reaction that includes both acid catalysis and proton assistance transfer shows the lowest energy barrier (25.0 kJ mol(-1)).
Publisher: American Chemical Society (ACS)
Date: 11-07-2022
DOI: 10.1021/ACS.JPCLETT.2C01616
Abstract: Gold nanoclusters (AuNCs) are atomic architectures that can be precisely tailored for catalytic applications. In this work, we studied two benchmark AuNCs, Au
Publisher: American Chemical Society (ACS)
Date: 13-11-2013
DOI: 10.1021/JP405121S
Abstract: This work targets the structural preferences of D-ribose and 2-deoxy-D-ribose in water solution and solid phase. A theoretical DFT (B3LYP and M06-2X) and MP2 study has been undertaken considering the five possible configurations (open-chain, α-furanose, β-furanose, α-pyranose, and β-pyranose) of these two carbohydrates with a comparison of the solvent treatment using only a continuum solvation model (PCM) and the PCM plus one explicit water molecule. In addition, experimental vibrational studies using both nonchiroptical (IR-Raman) and chiroptical (VCD) techniques have been carried out. The theoretical and experimental results show that α- and β-pyranose forms are the dominant configurations for both compounds. Moreover, it has been found that 2-deoxy-D-ribose presents a non-negligible percentage of open-chain forms in aqueous solution, while in solid phase this configuration is absent.
Publisher: No publisher found
Date: 2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CP00948D
Abstract: The hydrogen evolution reaction (HER) catalysed by [NiFe] hydrogenases entails a series of chemical events involving great mechanistic interest.
Publisher: American Chemical Society (ACS)
Date: 26-07-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5CC09324D
Abstract: Mg has great potential as the basis for a safe, low cost energy storage technology, however, cycling of magnesium is difficult to achieve in most electrolytes.
Publisher: Wiley
Date: 05-05-2015
Abstract: The biochemically important interconversion process between aldoses and ketoses is assumed to take place via 1,2-enediol or 1,2-enediolate intermediates, but such intermediates have never been isolated. The current work was undertaken in an attempt to detect the presence of the 1,2-enediol structure of glycolaldehyde in alkaline medium, actually a 1,2-enediolate, and to try to clarify the scarce data existing about both the formation of deprotonated enediol and the aldo-enediolate equilibrium. The Raman spectra of neutral and basic solutions were recorded as a function of time for eleven days. Several bands associated with the presence of the enediolate were observed in alkaline medium. Glycolaldehyde exists as three different structures in aqueous solution at neutral pH, that is, hydrated aldehydes, aldehydes and dimers, with a respective ratio of approximately 4:0.25:1. Additionally, the formation of Z-enediolate forms takes place at basic pH, together with an increase in the concentration of aldehyde species, such as 2-oxoethan-1-olate, and a decrease in the concentrations of the hydrated aldehyde and dimeric forms. The theoretical ratio of ≈1.5:1 for aldehyde:Z-enediolate reproduces the experimental Raman spectrum in basic medium, with an additional contribution of the previously mentioned ratio between the hydrated aldehyde and dimeric forms. Finally, Raman spectroscopy allowed us to monitor the enolization of this carbohydrate model and conclude that aldo-enediol tautomerism-formally aldo-enediolate-happens when a suitable amount of basic species is added.
Publisher: Springer Science and Business Media LLC
Date: 24-01-2012
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0CC90341H
Publisher: Wiley
Date: 11-10-2018
Publisher: American Chemical Society (ACS)
Date: 13-05-2020
Publisher: Wiley
Date: 02-01-2019
Abstract: A new base metal catalyzed sustainable multicomponent synthesis of pyrroles from readily available substrates is reported. The developed protocol utilizes an air- and moisture-stable catalyst system and enables the replacement of themutagenic α-haloketones with readily abundant 1,2-diols. Moreover, the presented method is catalytic in base and the sole byproducts of this transformation are water and hydrogen gas. Experimental and computational mechanistic studies indicate that the reaction takes place through a combined acceptorless dehydrogenation hydrogen autotransfer methodology.
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3FD00087G
Abstract: In this paper we set out to provide an overview of different approaches to activation of dinitrogen and their commonalities.
Publisher: Wiley
Date: 03-09-2018
Publisher: Wiley
Date: 12-2012
DOI: 10.1002/POC.3017
Publisher: Elsevier BV
Date: 06-2021
Publisher: Wiley
Date: 05-11-2018
Abstract: Very stable in operando and low-loaded atomic molybdenum on solid-support materials have been prepared and tested to be catalytically active for N
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2CY00389A
Abstract: Metals are common electrocatalysts for N 2 -into-NH 3 reduction. In protic media, H + competes with N 2 to be reduced into H 2 . NO x , common air pollutants, are predicted to be more selectively converted into NH 3 than N 2 , and even more than H + into H 2 .
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9DT00841A
Abstract: New [Au(IPr)(CHR 2 )] complexes have been synthesised through protonolysis reactions of [Au(IPr)(OH)] with moderately acidic substrates, CH 2 R 2 .
Publisher: American Chemical Society (ACS)
Date: 12-02-2019
DOI: 10.1021/ACS.INORGCHEM.8B02812
Abstract: The mechanism for Hydrogen Evolution Reaction (HER) in [NiFe] hydrogenase enzymes distinguishes them from inorganic catalysts. The first H
Publisher: American Chemical Society (ACS)
Date: 16-04-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3CP55489A
Abstract: Two stable minima for the 1 : 1 heterodimer of CO 2 : SO 2 , both bound by about 2 kcal mol −1 . Binding is dominated by charge transfer from O lone pairs of SO 2 to CO π* antibonding orbitals.
Publisher: American Chemical Society (ACS)
Date: 24-02-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9DT03379C
Abstract: The proposed reaction mechanism for the unprecedented direct transformation of primary alcohols into alkenes catalysed by Mn(i)-PNP complexes consists of two cycles. First, the acceptorless dehydrogenation of the alcohol into aldehyde is produced via a concerted mechanism. Secondly, in an excess of hydrazine, hydrazone is formed and reacts with the aldehyde to produce olefins. This process, taking place in base-free conditions, is characterised by the diastereoselective formation of diazenyl intermediates. Based on DFT data, the generation of the (S
Publisher: American Chemical Society (ACS)
Date: 12-01-2015
DOI: 10.1021/JP511828H
Abstract: SOF2, SOFCl, and SOCl2 were each paired with a series of N bases. The potential energy surface of the binary complexes were characterized by MP2 calculations with double and triple-ξ basis sets, extrapolated to complete sets. The most stable configurations contained a S···N chalcogen bond with interaction energies as high as 6.8 kcal/mol. These structures are stabilized by a Nlp → σ*(S-Z) electron transfer (Z = O, F, Cl), complemented by Coulombic attraction of N to the σ-hole opposite the Z atom. N···S-F and N···S-Cl chalcogen bonds are stronger than N···S═O interactions. Formation of each chalcogen bond elongates all of the internal covalent bonds within SOXY, especially the S-Cl bond. Halogen-bonded (N···Cl-S) complexes were also observed, but these are more weakly bound, by less than 3 kcal/mol.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6EE01800A
Abstract: MXenes: potential catalysts for the electrochemical synthesis of ammonia.
Publisher: Wiley
Date: 27-06-2017
Publisher: Springer Science and Business Media LLC
Date: 13-02-2015
Publisher: Wiley
Date: 11-10-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5CC07942J
Abstract: DFT investigations on beryllium-doped boron nitride meshes or sheets (BNs) predict the existence of a very reactive kind of novel material capable of spontaneously reducing the first hydrogenation step in the CO 2 conversion mechanism.
Publisher: Springer Science and Business Media LLC
Date: 30-03-2012
Publisher: AIP Publishing
Date: 15-01-2014
DOI: 10.1063/1.4861432
Abstract: Ab initio and density functional theory calculations are used to examine complexes formed between H2CO and H2CS with 1, 2, and 3 molecules of SO2. The nature of the interactions is probed by a variety of means, including electrostatic potentials, natural bond orbital, atoms in molecules, energy decomposition, and electron density redistribution maps. The dimers are relatively strongly bound, with interaction energies exceeding 5 kcal/mol. The structures are cyclic, containing both a O/S⋯S chalcogen bond and a CH⋯O H-bond. Addition of a second SO2 molecule leads to a variety of heterotrimer structures, most of which resemble the original dimer, where the second SO2 molecule engages in a chalcogen bond with the first SO2, and a C⋯O attraction with the H2CX. Some cooperativity is apparent in the trimers and tetramers, with an attractive three-body interaction energy and shortened intermolecular distances.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CP02453J
Abstract: Graphene-like carbon nitride (g-C 3 N 4 ), a metal-free 2D material that is of interest as a CO 2 reduction catalyst, is stabilised by corrugation in order to minimise the electronic repulsions experienced by the N lone pairs located in their structural holes.
Publisher: Springer Science and Business Media LLC
Date: 10-07-2012
Publisher: Elsevier BV
Date: 05-2015
Publisher: Springer Science and Business Media LLC
Date: 22-10-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7EE02716H
Abstract: High faradaic efficiency reduction of N 2 to NH 3 is achieved in ionic liquid media under ambient conditions.
Publisher: Wiley
Date: 05-11-2018
Publisher: American Chemical Society (ACS)
Date: 20-10-2020
Location: Spain
Location: Saudi Arabia
Location: No location found
Location: No location found
No related grants have been discovered for Luis Miguel Azofra.